Tips From The Pros

HOW TO LOOK AT TURFGRASS – PART 2: SIGHT-TURFING IN THE FIELD

Last month, I discussed some of the principles and challenges involved in developing your observational turfgrass management skills. So now that you have your proper light conditioners (sunglasses) ready, let’s take this knowledge out to the field. Remember, the goal here is to use these sight-turfing skills to both improve the health and condition of the turfgrass playing surface as well as the efficiency of your maintenance program.

The idea behind sight-turfing:

There is an old adage about how great scientists “See what they are not looking for”. This is also the goal for the observational turfgrass manager. You do not want to really look for anything. You want to look at the grass stand. What grabs your eye first? Usually it will be any tonal contrast, anything that stands out, anything not green. A good example is a drought stressed area of turfgrass. The early signs are a slightly blue-purplish tint to the grass canopy in that area.

Each time you mow or walk your field, take the opportunity to scan and notice. Never pass-over what you notice. Never walk past anything “off’ without making your best educated guess as to why it is that way. Distressed, unhappy grass reflects light differently than healthy grass and early detection and remedy skills are what separates the average and great turfgrass managers.

Reflected light. That is how turfgrass communicates with “Grass-whisperers”.

Timing:

Anyone who has spent a lot of time on a particular turfgrass field knows that it will look different at different times of the day. As light conditions change throughout the day and seasons, the sunlight’s intensity and angles change, as does the grass-reflected light you see when sight turfing. I really like dusk and dawn. The sunlight must pass though more atmosphere before reflecting off the grass. This filters out more of the easily scattered blue light. Movie-makers like this time of day for shooting. Toning down the blue brings better clarity and contrast. It’s the idea behind the classic blue-blockers sunglass technology. (They actually make pretty good sight-turfing glasses in my experience. (Best at bright mid-day sunshine when there is a lot of blue light bouncing around).

Early morning also will sometimes have the advantage of dew on the grass. It’s a great time to see the uniformity in the stand of turfgrass as well as gage relative health of the plant on various parts of your field.

Sun Angle:

Since we are analyzing reflected sunlight, the angle of the sun and our viewing position in relation to it is key. Whenever I notice something, I compare what I see changing my view from sun-at-my-back to sun-at-my-face. In my experiences, it is looking sun-in-face where we see the most reflected sunlight and with good sunglasses can tease-out slight differences better.

Looking at same area from two different sun angles. Notice how the sun-in-face angle shows early signs of drought stress, whereas looking at same area sun-at-back, the drought stress does not show. ©Ross Kurcab, CSFM

I remember undershooting my irrigation in the days leading up to a Sunday afternoon game. I blame the weather forecasters, but that’s another story. We knew things were too dry that morning, but with TV cameras up and running everywhere for pre-game shows, you don’t want to run the irrigation system. Any slip during the game would have directors running video of you “watering-down” the field before the game. So we used hose-teams. For some reason, that was seen as good groundsmanship and attention to detail.

We undershot our game-day wilt-patrol with hose teams also and the grass went into drought stress. By the second half, it was pretty significant. It was interesting as a sight-turfer to have people on one sideline asking me “what’s wrong with the turf, some disease?” This was the sun-in-face side of the stadium. The other side of the field, with sun-at-back position, everything looked fine. The main TV camera side, like most stadiums, are on the sun-at-back position, so the field looked fine on TV.

This is when I realized that a lower sun angle and a sun-in-face viewing position will give the earliest clues to trouble in the turf.

Stadium Lights:

If you have seen your field at night under stadium lights, it gives a different look to the turfgrass. To me, the grass generally get a more limey-green tint to it. Visible mowing patterns tend to get washed-out and less distinct. The intensity of reflected light is far less than bright sunshine. The light is being reflected off the grass from several angles instead of a predominately single angle during daylight. As a sight turfer, you lose your sun-in-face advantage and while it may be a pleasing environment to players and viewing fans, it is not very good for sight turfing in my opinion.

Stadium lights tend to wash-out mower patterns, lighten the green tint of the grass and make sight-turfing difficult compared to daytime sunshine. ©Ross Kurcab, CSFM

Watch the games:

Observe how your turfgrass performs during play. Analyze ball bounce/roll, footing, divoting, different shoe types, with different position-players. Analyze the traffic-damage and play after the games as you clean-up the field. Lie on your belly in push-up position to get a good view of the level of divoting going on. Get feedback from players and coaches on field playing performance.

Trivia: Did you know that in 2011 NFL owners enacted what some call “The Boise State Rule” which mandated all league fields be green in color?

Turf Tips 101: More Tips on Sight-Turfing

When you notice something off in the turfgrass stand, always investigate. Open-up a mini case file on the issue and develop a hypothesis to explain it. A hypothesis is simply a proposed explanation for an observable phenomenon. It could be a disease complex just beginning to express symptoms. Maybe it’s a simple yellowing of the turf in a few areas. Whatever it is, get a theory going and think of ways you can test the theory.

My first question is like a dichotomous key. Are the symptoms/signs a natural interaction with other organisms (biotic malady)? Or are they more man-made or physical in nature (abiotic malady). Anything in the form of a straight line is usually man-caused. Nature doesn’t usually work in straight lines, but man loves straight lines.

This read-and-react style of turfgrass observation relies heavily on your understanding how the turfgrass plants grow and develop. Different species used for turfgrasses have different growth habits. A thorough knowledge of the plant is key in building your hypothesis. A simple example of this is a summertime canopy burn of some type. This type of high temperature injury is usually caused by something, usually dark in color, being left on the turf. The item is quick to heat up in the summer sun and can begin to burn the turfgrass, killing tissue in as quickly as a few minutes in some circumstances. Closer inspection of the damaged plant will often reveal that only the leaves, or leaf tips are burned. The sight-turfer knows how the leaf blades grow and develop. He/she isn’t worried because it will simply grow out in a few days to a week and the damaged, unsightly burned leaves will be mowed off.

The conversion crew left two advertising boards on the grass while they took a break in mid-summer. The heat damage was not as serious as it appeared. The damage was only on the leaf tips. The crowns and roots were fine. “Grow-it and mow-it” was the remedy. ©Ross Kurcab, CSFM

Scan the field on a macro level every time you walk over or by it. Get down and look at several areas on a micro level. Dig-out and separate a few individual plants and examine them.

Roots:

How do the roots look? Healthy turfgrass will have deep, white and turgid roots. Stressed root systems will be more brownish in color, thinner (less plump and turgid) and shallow. Do the roots smell like a good earthy greenhouse or like dank, rotting manure? White, plump roots store carbohydrate reserves that can show you the grass plant’s potential to recover. Without some carbohydrate reserves underground, it will be a slow recovery with spreading grasses and time to overseed for bunch type grasses. Keep in mind the season. Cool-season grasses like Kentucky bluegrasses and Perennial ryegrasses will have the best roots in the spring and fall and may be naturally stressed in mid-summer to some degree. Bermudagrasses, like all warm-season grasses, will show their best roots in the mid-summer heat and will not be as prolific in the cooler temps and shorter days of spring and fall.

Leaves:

If you see something off in the leaves, determine if the malady is only on newer, older, or all leaves. Certain nutrient deficiencies, depending on their mobility within the grass plant will express yellowing on new or older leaves. For example, nitrogen is relatively mobile within the plant. The grass plant will redistribute N from older to newer leaves in scarcity. So a yellowing of older leaves may be a signal for more nitrogen. If, however, the yellowing is in the newer leaves, you might suspect something like iron deficiency perhaps as iron is relatively immobile in the plant and can’t be “redistributed” from older to newer leaves in scarcity.

Is the malady on the outer tip-portion of the leaves, or distributed up and down the length of the leaves?

Crown:

How does the all-important crown of the grass look? Like roots, you want to see a white, plump crown at or near the soil surface part of the plant. This is the best meristematic type tissue to regenerate re-growth and recovery from. If you have live crowns, you have a chance at recovery. If the crowns are shot, especially on turfgrasses with a bunch-type growth habit, you may start to consider seed or sodding options.

Lift your sunglasses up and down to get color perspective comparing the filtered and unfiltered view of the turfgrass. Change your viewing position in relation to the sun. Look sun-at-back and sun-in-face and also sun-to-the-side.

Change sunglasses, look with your naked eye, change your position and get every possible look you can at the area. ©Ross Kurcab, CSFM

Teach your turf team to be good sight-turfers. This can be a powerful force-multiplier as everyone sees things a little differently.

Bring in a colleague or two to look at tough issues. Don’t “pre-feed” them your conclusions. Give them time and space to see things their way.

Develop an action plan:

Manage the turf to the weakest point, within reason. For example, we often irrigate to the needs of the driest part of the field.

Do no (or limited) harm. Sometimes doing nothing is best. Grass knows what to do generally better than we do. Stop the principle stressor and grasses will often find their way back best. It may not be worth the stress of putting a tractor on the turf, for example, to carry out a remedy treatment that only has slight benefits.

Is the issue on the playing surface a safety issue? Playability issue? Appearance issue? Combination? Safety issues must be addressed before any play on the field. Playability issues may be closely related with field safety issues and must be carefully considered after consultation with coaches, referees and players. Appearance issues are generally less serious and may just be a temporary embarrassment.

Consider timelines and how many days you have for recovery to an acceptable level.

Boil-down your plan to a single, simple sentence. Take action when you have defined the most-likely problem, the best solution and the associated costs of remediation.

In some situations, it may be best to try the remedy on a small sample-plot or two on the field before treating the entire field. This is a good tactic to try to solidify a hunch before proceeding. Finish-out this sentence. “If the malady is caused by what I suspect, this treatment will help because ______”

You have to do the work correctly, checking/monitoring constantly, or none of this matters. ©Ross Kurcab, CSFM

You have to do the treatments correctly, or you can’t rely on the outcomes. Always monitor the work. Just checking the start of a procedure is no good. Clogged aerator tines, for example, may not occur until well into the treatment but can ruin the results anyway. Catch a problem in a treatment process early and it’s not a problem. Keep an inventory of well-maintained and calibrated equipment.

Try a control plot or two when doing any treatment. This is a small area in a non-critical part of the field where you do not perform whatever the treatment is. This can help determine how well your treatment has addressed the malady. This may be as simple as laying down a single or ½ sheet of plywood in a few spots for a corrective fertility application. Now you have a “check-plot” to compare with the rest of the field.

Post-game field clean-up is a great time to evaluate field performance. ©Ross Kurcab, CSFM

Resources of the month:

Think all this is crazy talk? Think again. Measuring the reflected light off plant has long been used in research. Now, we are seeing a few hand-held units available to industry that may help with your sight-turfing. This technology will get better I believe and become a commonly useful tool. The challenge, it seems to me, is how to make sense of the readings. At what level of green reflected light, for example, can we declare a nitrogen deficiency? So we need more work to “calibrate” the readings to specific maladies. Changing source light (Sunlight) conditions further complicate the challenge.

Spectrum Technologies offers the Field Scout CM 1000 NDVI Chlorophyll Meter in a point-and-shoot application. They also offer the Field Scout TCM 500 NDVI Turf Color Meter “Uses an internal light source to negate the effect of sunny versus cloudy conditions”

End Quote:

“To acquire knowledge, one must study; but to acquire wisdom, one must observe.” – Marilyn vos Savant. (Highest recorded IQ - Guinness Book of Records)